1. Field of the Invention
The present invention relates to a method of treating matter in a body vessel or cavity, especially to removing undesired obstructing material, such as thrombus, from a body vessel or cavity having an obstruction, by employing an interchangeable and separable catheter system for alternatively incorporating the principles of a rheolytic thrombectomy catheter or the principles of a crossflow thrombectomy catheter, or of the simultaneous use of the principles of both the rheolytic thrombectomy catheter and the crossflow thrombectomy catheter.
More particularly, the present invention relates to a method of treatment of the human body by means of an elongated device which may be a single catheter assembly or a multiple component catheter assembly and which is suitable for use through percutaneous or other access, for endoscopic procedures, or for intraoperative use in either open or limited access surgical procedures. Still more particularly, the present invention relates to a method of treatment of the human body involving use of an elongated device in the form of a rheolytic thrombectomy catheter or, alternately, in the form of a fluid jet thrombectomy catheter, the latter hereinafter termed crossflow thrombectomy catheter, and having a commonly used outer catheter assembly, each device being incorporated for fragmentation and removal of thrombus or other unwanted material from blood vessels or body cavities, and each device using high velocity saline (or other suitable fluid) jets to macerate the thrombus or other unwanted material. The elongated device bears certain similarities to a known waterjet thrombectomy catheter and can be used as such, but differs therefrom in several material respects, a major distinction being in the provision of interchangeable alternate means which produce inwardly directed jets with or without crossflow jets. The crossflow jets create a recirculation flow pattern optimized for clearing a large cross section of mural thrombus or other similar material, the name crossflow thrombectomy catheter deriving from this major distinction. Further, the method of the present invention also involves a system constituted either by the combination of the elongated device with both pressurized fluid source means and exhaust regulation means or by the combination of the elongated device with only pressurized fluid source means.
2. Description of the Prior Art
Procedures and devices have been developed for ease in removing tissue and various deposits. Several such devices employ a jet of saline as the working tool to help break up the tissue deposit and further provide a suction means to remove the deposit. U.S. Pat. No. 5,135,482 to Neracher describes a hydrodynamic device for removal of organic deposit from a human vessel. A supply of saline is delivered by a high pressure duct to the distal end of a catheter. The saline exits the duct as a jet that is directed generally forward and directly toward the tissue to be broken up. The duct is contained within and can move axially with respect to a hose that is positioned around the duct. A vacuum suction is applied to the hose to remove the debris that is created from the broken-up tissue. This device is not intended to pass through tortuous pathways found in the fragile vessels of the body, and any attempt to employ the device for such purpose would be far too traumatic to the patient.
Another drainage catheter, described by Griep in U.S. Pat. No. 5,320,599, has a discharge channel and a pressure channel. The channels are formed into a single catheter tube such that the two tubes are fixed with respect to each other.
Waterjet thrombectomy catheters have been described in which a distal-to-proximal-directed waterjet(s) flow(s) past a window, orifice or gap at the distal end of the catheter, re-entering the catheter and pushing flow through an evacuation lumen. When placed in a vessel containing thrombus and activated, the high velocity jet(s) will entrain surrounding fluid and thrombus into the window, orifice or gap region, where the high shear forces of the jet(s) will macerate the thrombus. The macerated particles will be removed from the body by the pressure generated on the distal end of the evacuation lumen by the impingement of the high velocity waterjet(s).
A limitation of these waterjet thrombectomy catheters has been the inability to remove organized, wall-adherent thrombus from large vessels. In accordance with the method of the present invention, the single operator exchange fluid jet thrombectomy device described and utilized in the method overcomes this limitation by optimizing the recirculation pattern at the tip of the device to increase the drag force exerted on the mural thrombus to break it free from the vessel wall and allow it to be removed by the device.
Methods practiced with prior art devices often required the use of more than one operator where one operator must stabilize the guidewire while the second operator introduces the catheter over the guidewire into the anatomy.
The method of the present invention overcomes the disadvantages of the procedures using current devices by relying on an interchangeable catheter system utilizing either the rheolytic thrombectomy catheter or the crossflow thrombectomy catheter, each of which can be operated by one practitioner, and which offers multiple advantages over previous rheolytic thrombectomy catheter designs. More specifically, the method of the present invention is effectual for removal of unwanted deposits in the body, such as, but not limited to, deposits in bile ducts, the brain or other hematomas, and brain ventricles, for example.
The present invention, a single operator exchange fluid jet thrombectomy method, relies on use of a single operator exchange fluid jet thrombectomy device, which is a surgical device for removal of material such as thrombus from a vessel or other body cavity. As shown in one or more embodiments, the single operator exchange fluid jet thrombectomy device can function as a rheolytic thrombectomy catheter for removing tissue from a vessel or other body cavity and includes an outer catheter assembly common to any mode of operation, the commonly used outer catheter assembly of which is comprised of a manifold and a first tube or guide catheter having a lumen with an open distal end, the lumen being of a diameter sufficient to allow passage of an inner catheter assembly. One such inner catheter assembly as incorporated in use with the single operator exchange fluid jet thrombectomy device is comprised of a high pressure second tube having a high pressure lumen and a geometrically configured distally located jet emanator having one or more rearwardly directed orifices for directing one or more jets of saline toward the distal end of a flow director, a proximally located transitional stop fixed to the second tube adjacent to the second tube proximal end, and an exhaust tube. The inner catheter assembly is movable axially within the outer catheter assembly such that the proximally located transitional stop engages the proximally located stationary stop to hold the jet emanator in a desired relationship with respect to the distal end of the outer catheter assembly.
The single operator exchange fluid jet thrombectomy device provides a catheter combination for use as a rheolytic thrombectomy catheter including the first tube or guide catheter, being a part of a common use outer assembly, the first tube or guide catheter having a proximal end, a manifold attached thereto, an open distal end, and a lumen extending between the proximal end and the open distal end; the second tube, being a part of an inner catheter assembly, the second tube being separable from the first tube or guide catheter and being insertable within the lumen of the first tube or guide catheter, the second tube having a proximal end, a distal end, and a lumen extending between the proximal end and the distal end; a flow director having an inner body and an exhaust tube which may or may not be expandable, each being located near but not at the second tube distal end, a pressure operated sealable or closely fit annulus between the outer surface of the exhaust tube and the interior annular surface of the first tube or guide catheter, a jet emanator integrally formed at the distal end of the second tube or attached thereto by a bonding operation into which at least one jet orifice is machined or otherwise formed on the proximal side thereof to create a jet emanator for directing fluid proximally for thrombus ablation and subsequently through a lumen in the flow director and the lumen of the first tube or guide catheter, being also a part of the inner catheter assembly, the jet emanator and flow director, including the inner body thereof, being capable of passage through the lumen of the first tube or guide catheter and over a guidewire, and being characterized by the ability to provide a localized region of low pressure associated with a liquid flow directed generally proximally and into the inner body, into an exhaust tube, and into the lumen of the first tube or guide catheter through the distal end of the first tube or guide catheter. A variable displacement distance means for indexing an appropriate positional and variable relationship of the jet emanator to the distal end of the first tube or guide catheter is provided. A stop means is provided for limiting movement of the second tube and preferably includes a proximally located hemostasis nut/stop at the proximal end of a manifold of the outer catheter assembly and a proximally located filter housing/high pressure connection/stop assembly projecting outwardly from the proximal end of the second tube. When the second tube is advanced within the first tube or guide catheter, fluoro-imaging can be incorporated to provide adequate spacing and relationship between the jet emanator and the distal end of the first tube or guide catheter. This relationship is also referred to as variable displacement distance. Lateral positioning of the second tube within the first tube or guide catheter is readily accomplished during the first stage (insertion) in an unpressurized operational mode where the sealable or closely fit annulus is suitably sized to allow easy unrestricted passage of the second tube within and through the first tube or guide catheter. A representative exhaust tube is shown in many embodiments with additional reference to the following exhaust tube types including, but not limited to, an exhaust tube which can be compliant expandable where the diameter of the exhaust tube depends on applied pressure and subsequent restriction by the guide catheter, a non-compliant expandable exhaust tube where the diameter of the exhaust tube is dependent on the designed diameter or the exhaust tube can be not expandable, but closely fit to the first tube or guide catheter. During the operational pressurized mode, jetted saline causes an expandable exhaust tube to expand, thus partially or fully closing, restricting, modifying or eliminating the open annulus to pressure seal the first tube or guide catheter to the second tube, but still allowing movement relative to each other. In the alternative, a closely fit annulus incorporating a non-expandable exhaust tube offers partial but effective restrictive closing to substantially pressure seal or close the first tube or guide catheter to the second tube.
The above embodiment is utilized in a method of removing thrombus from an obstructed body vessel. The method includes the steps of:
a. providing a guidewire and an outer catheter assembly including a manifold, a first tube or guide catheter having an interior annular surface, a distal end, and an externally located stationary hemostasis nut/stop positioned at the manifold proximal end;
b. advancing the first tube or guide catheter proximal to a vascular site containing thrombus;
c. advancing the guidewire through the first tube or guide catheter and past the vascular site containing thrombus;
d. providing an inner catheter assembly including a second tube carrying a jet emanator at its distal end, a flow director including an expandable or non-expandable exhaust tube proximal of the jet emanator, and a transitional filter housing/high pressure connection/stop assembly at its proximal end;
e. advancing the inner catheter assembly to a desired position within the first tube or guide catheter, so that a gap or space proximal to the jet emanator extends past the distal end of the first tube or guide catheter, while the proximal end of the flow director remains proximal to the distal end of the first tube or guide catheter;
f. providing a high pressure saline supply to the second tube so as to cause at least one jet of saline to emanate from the jet emanator and to entrain thrombus into the gap or space where the thrombus is macerated and then pushed through the flow director and into the first tube or guide catheter for removal from the body; and,
g. providing impingement of at least one jet on the interior annular surface of an exhaust tube to create sufficient stagnation pressure to expand the exhaust tube against the interior annular surface of the first tube or guide catheter or utilize a closely fit annulus and force evacuation of debris through the flow director and the first tube or guide catheter out of the body with no need for additional suction.
In the method, the inner catheter assembly can be moved axially relative to both the first tube or guide catheter and guidewire to facilitate distal and proximal movement of the inner catheter assembly to remove thrombus distributed axially throughout the vasculature.
An alternate embodiment useful in the method includes a crossflow/flow director inserted into the common outer catheter assembly to function substantially as described above, but to include the features and functions of a crossflow thrombectomy catheter.
One significant aspect and feature of the method of the present invention is the use of a single operator exchange fluid jet thrombectomy device operable by one practitioner.
Another significant aspect and feature of the method of the present invention is the use of a single operator exchange fluid jet thrombectomy device having an outer catheter assembly which can accommodate various inner catheter assemblies configured to function either as a rheolytic thrombectomy catheter or as a crossflow thrombectomy catheter.
Another significant aspect and feature of the method of the present invention is the provision of a transitional filter housing/high pressure connection/stop assembly on the proximal end of the second tube which impinges a hemostasis nut/stop on the manifold to position the jet emanator at a defined distance beyond the distal end of the guide catheter.
Other significant aspects and features of the method of the present invention are the provisions of a transitional filter housing/high pressure connection/stop assembly proximally located at the end of the inner catheter assembly and a stationary hemostasis nut/stop proximally located on the outer catheter assembly which engage to prevent the inner catheter assembly from being excessively advanced, so that the exhaust tube proximal end does not become disengaged from the distal end of the first tube or guide catheter.
A further significant aspect and feature as found in additional embodiment groups employed in the method of the present invention is an annulus which is open for lateral movement of the inner catheter assembly within the outer catheter assembly during the initial unpressurized mode (insertion) and which can be modulated to a partially or fully closed position and sealed by jetted saline during the ablation process to provide maximum proximally directed saline flow with minimum or no leakage between the outer and inner catheter assemblies when thrombotic tissue is broken up and carried proximally.
Another significant aspect and feature of the method of the present invention is the provision of a flow director which can use either a compliant expandable, a non-compliant expandable, a non-expandable, non-compliant close fit, or a combination compliant/non-compliant exhaust tube.
Yet another significant aspect and feature of the method of the present invention is the ability to incorporate various emanator shapes, styles and designs.
Another significant aspect and feature of the method of the present invention is the ability to reduce cost aspect since effluent outflow or exhaust can be collected using a standard Y-connector.
Having thus described embodiments and significant aspects and features pertaining to the method of the present invention, it is the principal object of the present invention to provide a single operator exchange fluid jet thrombectomy method to remove undesired obstructing material such as thrombus from a body vessel or other body cavity.